1. Field of the Invention
The invention relates in general to a thermal color printer, and more particularly to a thermal color printer using infrared ray with amber ray, or infrared ray with blue ray for identifying different colorant regions on an ink sheet.
2. Description of the Related Art
Printers are commonly used for current computer users to print out data, like text data and colorful drawings. Theses colorful drawings could be an image downloaded from Internet or pictures captured by digital cameras.
Dot-impact printer, ink jet printer, laser jet printer, and thermal printer are examples of the most popular printers.
Whereas, there are two types of thermal printers: dye-sublimation printers and thermal wax printers. Different dyes or colorants in respective colorant regions of the ink sheet are printed onto print medium such as paper by ways of thermal-sublimation or thermal-transfer. Hence, dyes and colorant for a thermal printer should be thermally transferable. In other words, they can be printed onto print mediums when they are heated.
Ink sheet generally includes many colorant region sets, and each includes three colorant regions: a yellow (Y) region, a magenta (M) region and a cyan (C) region. Colorant region sets of certain ink sheets further include a black (K) region or/and an overlay (O) region. Herein, region Y, region M, region C, region K and region O respectively represent to the yellow region, the magenta region, the cyan region, the black region and the overlay region for simplicity. A black image formed from region K is usually with better quality than the one formed by mixing the YMC colorants. Region O, which is the so-called over-coating region, is used to protect other already printed colorants by forming a protective coating on the surface of the print medium.
It is an important subject for a thermal printer to precisely distinguish different colorant regions and print correct colorant onto print medium. Conventional techniques related to methods of identifying colorant region are disclosed in, for example, U.S. Pat. Nos. 4,496,955, 4,710,781, and 5,781,219.
Taking U.S. Pat. No. 5,781,219 as an example, the head sensor mark and the identification sensor mark are used to identify colorant regions on the ink sheet. In the first embodiment of the U.S. Pat. No. 5,781,219, the ink sheet includes region Y, region M, region C and region K. One side of the ink sheet further includes transparent parts. The head sensor mark is arranged on the transparent parts between region Y and region K. The identification sensor mark is arranged between region Y and region C.
The disadvantage of the technique according to U.S. Pat. No. 5,781,219 is stated as follows. If there is no enough distance between region C and region K, the sensors may not be able to correctly sense the beginning of region K, which causes misallocation. Increasing the distance between region C and region K is the common solution for misallocation, which however also increases the length of ink sheet. An ink sheet of larger length is of course of higher cost, which is not desirable. Similarly, in the fourth embodiment of U.S. Pat. No. 5781219, the identification sensor mark is arranged between region M and region C. There must be enough distance between region M and the identification sensor mark to correctly sense the identification sensor mark.
It is therefore an object of the invention to provide an improved thermal printer using colorful rays and infrared rays for colorant region identification with the auxiliary of black marks. Black marks are arranged between predetermined colorant regions, instead of being arranged at transparent parts. Therefore, the ink sheet is shorter than the conventional ones.
The invention achieves the above-identified objects by providing a new thermal printer, including an ink sheet, a printing head, a forwarding device, the first ray source and the first sensor and the second ray source and the second sensor. The ink sheet includes a yellow region, a magenta region, a cyan region, and a first mark. The three regions are arranged sequentially and the first mark is arranged at the beginning of the cyan region. The printing head is for printing colorants of the colorant regions onto a print medium. The forwarding device forwards the ink sheet to have a relative movement to the printing head. The first ray source and the first sensor detect the first mark and send out the first signal. The second ray source and the second sensor detect the colorant regions and send out a second signal. When the forwarding device forwards the ink sheet, which colorant region the printing head locates is determined by the first signal and the second signal.
It is therefore a further object to provide an ink sheet of a thermal printer. The location of each colorant region is identified by the first ray source and the second ray source. The ink sheet includes a yellow region, a magenta region and a cyan region, which are sequentially arranged on the ink sheet. The ink sheet further includes the first mark. The first mark is arranged at the beginning of the cyan region. The first ray emitted by the first ray source transmits through the yellow region, the magenta region and the cyan region. The first ray and the second ray emitted by the first and the second ray sources could not transmit through the first mark.
It is therefore another subject of the invention that a printing method of a thermal printer is disclosed. The thermal printer includes an ink sheet, an infrared ray source, an infrared ray sensor, an amber ray source, and an amber ray sensor. A yellow region, a magenta region, a cyan region and an overlay region are sequentially arranged on the ink sheet. The first and the second marks are respectively arranged at the beginning of the yellow region and the beginning of the cyan region. The first mark and the second mark are not transmitted by infrared ray and amber ray. The printing method includes the following steps. The ink sheet is first forwarded. Then, the process of forwarding the ink sheet is stopped and the colorant of the yellow region begins to be printed onto a print medium when the amber ray is sensed and the infrared ray is not sensed. In the process of printing, IR ray is not always shades. Next, the ink sheet is forwarded until amber ray is not sensed. After the forwarding of the ink sheet is stopped, colorant of the magenta region is printed onto the print medium. Then, the ink sheet is forwarded again until the infrared ray is not sensed. Colorant of the cyan region is then printed. Next, the ink sheet is forwarded until amber ray is sensed. Colorant of the overlay region is then printed.
It is therefore a further object of the invention to provide a printing method of a thermal printer. The thermal printer includes an ink sheet, an infrared ray source, an infrared ray sensor, an amber ray source, and an amber ray sensor. The ink sheet is sequentially arranged with a yellow region, a magenta region and a cyan region. The first mark is arranged at the beginning of the cyan region and the first mark can not be transmitted by the infrared ray and the amber ray. The printing method includes the following steps. The ink sheet is first forwarded and then stopped while the sensing result of amber ray is changed from low to high. Next, colorant of the yellow region is printed onto the print medium. The ink sheet is forwarded again until the sensing result of amber ray is low. Then the ink sheet is stopped and colorant of the magenta region is printed onto the print medium. The ink sheet is again forwarded until the sensing result of infrared ray is low. Next, the ink sheet is stopped and colorant of the cyan region is printed onto the print medium.
It is therefore a further object of the invention to provide a printing method of a thermal printer. The thermal printer includes an ink sheet, an infrared ray source, an infrared ray sensor, a blue ray source, and a blue ray sensor. The ink sheet sequentially includes a yellow region, a magenta region and a cyan region. The first mark, which is infrared ray and blue ray non-transmittable, is arranged at the beginning of the cyan region. The printing method includes the following steps. The ink sheet is forwarded until the sensing result of blue ray is from high to low. Then, the ink sheet is stopped and colorant of the yellow region is printed onto a print medium. The ink sheet is again forwarded until the sensing result of blue ray is high. The ink sheet is then stopped and colorant of the magenta region is printed onto the print medium. The ink sheet is next forwarded until the sensing result of infrared ray low. After the ink sheet is stopped, colorant of the cyan region is printed.
It is therefore a further object of the invention to provide a printing method of a thermal printer. The thermal printer includes an ink sheet, an infrared ray source, an infrared ray sensor, a blue ray source, and a blue ray sensor. The ink sheet sequentially includes a yellow region, a magenta region, a cyan region and a black mark. The first mark and the second mark are respectively arranged at the beginning of the yellow region and the beginning of the cyan region. The first mark and the second mark are both infrared ray and blue ray non-transmittable. The printing method includes the following steps. The ink sheet is first forwarded until the sensing result of blue ray is low and the sensing result of infrared ray is low. The forwarding of the ink sheet is then stopped and colorant of the yellow region is printed onto a print medium. The ink sheet is then forwarded until the sensing result of blue ray is high. After the ink sheet is stopped, colorant of the magenta is printed onto the print medium. The ink sheet is again forwarded until the sensing result of infrared ray is low. After the ink sheet is stopped colorant of the cyan region is printed onto the print medium. Next, the ink sheet is forwarded until the sensing result of blue ray is low. After the forwarding of the ink sheet is stopped, colorant of the overlay region is printed onto the print medium.
Other objects, features, and advantages of the invention will become apparent from the following detailed description of the preferred but non-limiting embodiments. The following description is made with reference to the accompanying drawings.